A small electric immersion heater is placed at the bottom of a glass beaker containing water. The beaker stands on a wooden table in a room at 25∘C. After the water starts boiling, answer the following:
(i) Identify the predominant mode of heat transfer
(a) from the heating coil to the water in contact with it,
(b) within the bulk of the water,
(c) from the outer surface of the glass beaker to the surrounding air,
(d) from the hot water surface to the room.
(ii) Justify each identification with appropriate reasoning referring to the physical conditions present.
(iii) Suggest any TWO practical modifications to the set-up that would reduce heat loss to the surroundings, and briefly state which mode each modification aims to minimise.